#include <bits/stdc++.h>
using namespace std;
template <typename T1, typename T2>
inline void chkmin(T1 &x, T2 y) {
  if (x > y) x = y;
}
template <typename T1, typename T2>
inline void chkmax(T1 &x, T2 y) {
  if (x < y) x = y;
}
inline int readChar();
template <class T = int>
inline T readInt();
template <class T>
inline void writeInt(T x, char end = 0);
inline void writeChar(int x);
inline void writeWord(const char *s);
static const int buf_size = 4096;
inline int getChar() {
  static char buf[buf_size];
  static int len = 0, pos = 0;
  if (pos == len) {
    pos = 0, len = fread(buf, 1, buf_size, stdin);
  }
  if (pos == len) {
    return -1;
  }
  return buf[pos++];
}
inline int readChar() {
  int c = getChar();
  while (c <= 32) {
    c = getChar();
  }
  return c;
}
template <class T>
inline T readInt() {
  int s = 1, c = readChar();
  T x = 0;
  if (c == '-') s = -1, c = getChar();
  while ('0' <= c && c <= '9') x = x * 10 + c - '0', c = getChar();
  return s == 1 ? x : -x;
}
static int write_pos = 0;
static char write_buf[buf_size];
inline void writeChar(int x) {
  if (write_pos == buf_size)
    fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
  write_buf[write_pos++] = x;
}
template <class T>
inline void writeInt(T x, char end) {
  if (x < 0) writeChar('-'), x = -x;
  char s[24];
  int n = 0;
  while (x || !n) s[n++] = '0' + x % 10, x /= 10;
  while (n--) writeChar(s[n]);
  if (end) writeChar(end);
}
inline void writeWord(const char *s) {
  while (*s) writeChar(*s++);
}
struct Flusher {
  ~Flusher() {
    if (write_pos) fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
  }
} flusher;
using namespace std;
const int MAXN = 300300;
int n;
int a[MAXN];
int b[MAXN];
long long sumsa[MAXN];
long long sumsb[MAXN];
int dp[MAXN];
int ul[MAXN];
int dl[MAXN];
map<long long, int> mf, fa, fb;
map<int, int> dm[MAXN];
int solve(int l, int r) {
  if (l == r) {
    return dp[l];
  }
  if (dm[l].count(r)) {
    return dm[l][r];
  }
  dm[l][r] = dp[min(l, r)];
  if (l < r) {
    if (dl[r] != -1) {
      chkmax(dm[l][r], solve(l, dl[r]) + 1);
    }
  } else {
    if (ul[l] != -1) {
      chkmax(dm[l][r], solve(ul[l], r) + 1);
    }
  }
  return dm[l][r];
}
int main() {
  n = readInt();
  for (int i = 1; i <= n; i++) {
    a[i] = readInt();
    sumsa[i] = sumsa[i - 1] + a[i];
  }
  for (int i = 1; i <= n; i++) {
    b[i] = readInt();
    sumsb[i] = sumsb[i - 1] + b[i];
  }
  mf[0] = 0;
  fa[0] = 0;
  fb[0] = 0;
  ul[0] = -1;
  dl[0] = -1;
  for (int i = 1; i <= n; i++) {
    dp[i] = dp[i - 1];
    long long cf = sumsa[i] + sumsb[i];
    if (mf.count(cf)) {
      chkmax(dp[i], 1 + dp[mf[cf]]);
    }
    mf[cf] = i;
    ul[i] = ul[i - 1];
    dl[i] = dl[i - 1];
    if (fa.count(sumsa[i])) {
      if (ul[i] < fa[sumsa[i]]) {
        ul[i] = fa[sumsa[i]];
      }
    }
    if (fb.count(sumsb[i])) {
      if (dl[i] < fb[sumsb[i]]) {
        dl[i] = fb[sumsb[i]];
      }
    }
    if (ul[i] != -1) {
      chkmax(dp[i], solve(ul[i], i) + 1);
    }
    if (dl[i] != -1) {
      chkmax(dp[i], solve(i, dl[i]) + 1);
    }
    fa[sumsa[i]] = i;
    fb[sumsb[i]] = i;
  }
  writeInt(dp[n], '\n');
  return 0;
}
