#include <bits/stdc++.h>
using namespace std;
template <typename T>
void read(T &x) {
  x = 0;
  char ch = getchar();
  int fh = 1;
  while (ch < '0' || ch > '9') {
    if (ch == '-') fh = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  x *= fh;
}
template <typename T>
void write(T x) {
  if (x < 0) x = -x, putchar('-');
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
}
template <typename T>
void writeln(T x) {
  write(x);
  puts("");
}
const double eps = 1e-3;
int n, m;
double w, v;
double rest[55];
vector<pair<int, double>> ans[55];
set<int> st[55];
int dcmp(double a, double b) {
  if (fabs(a - b) < eps) return 0;
  if (a < b) return -1;
  return 1;
}
signed main() {
  cin >> n >> w >> m;
  v = n * w / m;
  for (int i = 1; i <= m; ++i) rest[i] = v;
  int cur = 1;
  for (int i = 1; i <= n; ++i) {
    double u = w;
    while (cur <= m) {
      if (dcmp(rest[cur], u) >= 0) {
        ans[cur].push_back(make_pair(i, u));
        rest[cur] -= u;
        if (dcmp(rest[cur], 0) == 0) rest[cur] = 0, cur++;
        u = 0;
        break;
      } else {
        ans[cur].push_back(make_pair(i, rest[cur]));
        u -= rest[cur];
        if (dcmp(u, 0) == 0) u = 0;
        rest[cur] = 0;
        cur++;
      }
    }
  }
  for (int i = 1; i <= m; ++i) {
    for (auto j : ans[i]) st[j.first].insert(i);
  }
  bool flag = true;
  for (int i = 1; i <= n; ++i)
    if (st[i].size() > 2) {
      flag = false;
      break;
    }
  if (flag) {
    cout << "YES" << endl;
    for (int i = 1; i <= m; ++i) {
      for (auto j : ans[i])
        cout << j.first << ' ' << fixed << setprecision(6) << j.second << ' ';
      cout << endl;
    }
  } else
    cout << "NO" << endl;
  return 0;
}
