#include <bits/stdc++.h>
namespace MyMinMax {
template <typename T>
inline T mn(T x, T y) {
  return x < y ? x : y;
}
template <typename T>
inline T mx(T x, T y) {
  return x > y ? x : y;
}
template <typename T>
inline void chmin(T &x, T y) {
  (x > y) && (x = y);
}
template <typename T>
inline void chmax(T &x, T y) {
  (x < y) && (x = y);
}
}  // namespace MyMinMax
using namespace MyMinMax;
namespace IO {
char BB[1 << 18], *SS = BB, *TT = BB;
template <typename T>
inline void read(T &x) {
  x = 0;
  int fu = 1;
  char c =
      (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
           ? EOF
           : *SS++);
  while (c > 57 || c < 48) {
    if (c == 45) fu = -1;
    c = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
             ? EOF
             : *SS++);
  }
  while (c <= 57 && c >= 48) {
    x = x * 10 + c - 48;
    c = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
             ? EOF
             : *SS++);
  }
  x *= fu;
}
template <typename T>
inline void read(T *bg, T *ed) {
  while (bg != ed) read(*bg++);
}
inline void read(char &ch) {
  ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
            ? EOF
            : *SS++);
  while (ch <= 32)
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
}
inline void read(char *s) {
  char ch =
      (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
           ? EOF
           : *SS++);
  while (ch <= 32)
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  while (ch > 32)
    *s++ = ch,
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  *s = '\0';
}
inline void sread(char *s) {
  char ch =
      (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
           ? EOF
           : *SS++);
  while (ch < 32)
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  while (ch >= 32)
    *s++ = ch,
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  *s = '\0';
}
inline void pread(char *&s) {
  char ch =
      (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
           ? EOF
           : *SS++);
  while (ch <= 32)
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  while (ch > 32)
    *s++ = ch,
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  *s = '\0';
}
inline void spread(char *&s) {
  char ch =
      (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
           ? EOF
           : *SS++);
  while (ch < 32)
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  while (ch >= 32)
    *s++ = ch,
    ch = (SS == TT && (TT = (SS = BB) + fread(BB, 1, 1 << 18, stdin), SS == TT)
              ? EOF
              : *SS++);
  *s = '\0';
}
template <typename T, typename... Args>
inline void read(T &x, Args &...args) {
  read(x);
  read(args...);
}
char out[1 << 18], *Out = out;
inline void putcha(char x) {
  *Out++ = x;
  if (Out - out >= (1 << 18)) fwrite(out, 1, Out - out, stdout), Out = out;
}
template <typename T>
inline void fprint(T x) {
  if (x < 0) putcha(45), x = -x;
  if (x > 9) fprint(x / 10);
  putcha(x % 10 + 48);
}
template <typename T>
inline void print(T x) {
  fprint(x);
  putcha(10);
}
inline void print(char *ch) {
  while (*ch != '\0') putcha(*(ch++));
  putcha(10);
}
inline void put(char *ch) {
  while (*ch != '\0') putcha(*(ch++));
}
inline void print(const char *ch) {
  while (*ch != '\0') putcha(*(ch++));
  putcha(10);
}
inline void put(const char *ch) {
  while (*ch != '\0') putcha(*(ch++));
}
template <typename T, typename... Args>
inline void print(T x, Args... args) {
  fprint(x);
  putcha(32);
  print(args...);
}
template <typename... Args>
inline void print(const char *ch, Args... args) {
  while (*ch != '\0') putcha(*(ch++));
  putcha(32);
  print(args...);
}
template <typename... Args>
inline void print(char *ch, Args... args) {
  while (*ch != '\0') putcha(*(ch++));
  putcha(32);
  print(args...);
}
template <typename T, typename... Args>
inline void printl(T x, Args... args) {
  fprint(x);
  putcha(10);
  print(args...);
}
template <typename... Args>
inline void printl(const char *ch, Args... args) {
  while (*ch != '\0') putcha(*(ch++));
  putcha(10);
  print(args...);
}
template <typename... Args>
inline void printl(char *ch, Args... args) {
  while (*ch != '\0') putcha(*(ch++));
  putcha(10);
  print(args...);
}
template <typename T>
inline void sprint(T x) {
  fprint(x);
  putcha(32);
}
template <typename T, typename... Args>
inline void sprint(T x, Args... args) {
  fprint(x);
  putcha(32);
  sprint(args...);
}
template <typename T>
inline void sprint(T *bg, T *ed) {
  while (bg != ed) sprint(*bg++);
}
template <typename T>
inline void print(T *bg, T *ed) {
  while (bg != ed) sprint(*bg++);
  putcha(10);
}
template <typename T>
inline void printl(T *bg, T *ed) {
  while (bg != ed) print(*bg++);
}
class AutoFlush {
 public:
  ~AutoFlush() { fwrite(out, 1, Out - out, stdout); }
} __AutoFlush;
}  // namespace IO
using namespace IO;
int n, m;
long long id[300005], od[300005], c[300005];
int a[300005], b[300005];
int ca, cb;
struct EDGE {
  int u, v;
  long long w;
  EDGE() {}
  EDGE(int u, int v, long long w) : u(u), v(v), w(w) {}
};
EDGE ans[300005];
int tp = 0;
inline bool cmp(int &x, int &y) { return c[x] > c[y]; }
int main() {
  read(n, m);
  for (int i = 1; i <= m; ++i) {
    int u, v, w;
    read(u, v, w);
    id[v] += w;
    od[u] += w;
  }
  for (int i = 1; i <= n; ++i) {
    c[i] = id[i] - od[i];
    if (c[i] < 0) a[++ca] = i;
    if (c[i] > 0) b[++cb] = i;
  }
  std ::sort(a + 1, a + ca + 1, cmp);
  std ::sort(b + 1, b + cb + 1, cmp);
  int it = 1;
  for (int i = 1; i <= ca; ++i) {
    while (it <= cb && c[a[i]] < 0) {
      long long t = mn(-c[a[i]], c[b[it]]);
      c[a[i]] += t;
      c[b[it]] -= t;
      ans[++tp] = EDGE(a[i], b[it], t);
      if (!c[b[it]]) ++it;
    }
  }
  print(tp);
  for (int i = 1; i <= tp; ++i) print(ans[i].u, ans[i].v, ans[i].w);
}
