#include <bits/stdc++.h>
using namespace std;
const int mn = 1 * (int)(1e5) + 10;
const int mod = 1 * (int)(1e9) + 7;
const int mm = 1 * (int)(1e3) + 10;
const int base = 1 * (int)(1e9);
const bool aNs = 0;
int tt, ntest = 1;
void docfile() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  if (ifstream("test"
               ".inp")) {
    freopen(
        "test"
        ".inp",
        "r", stdin);
    if (!aNs)
      freopen(
          "test"
          ".out",
          "w", stdout);
    else
      freopen(
          "test"
          ".ans",
          "w", stdout);
  } else if (ifstream(""
                      ".inp")) {
    freopen(
        ""
        ".inp",
        "r", stdin);
    freopen(
        ""
        ".out",
        "w", stdout);
  }
}
template <typename T>
void read(T& x) {
  x = 0;
  T f = 1;
  char ch = getchar();
  while (!isdigit(ch)) f = ch == '-' ? -f : f, ch = getchar();
  while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
  x *= f;
}
template <typename T>
void write(T a) {
  if (a < 0) {
    putchar('-');
    write(-a);
    return;
  }
  if (a < 10) {
    putchar('0' + a);
    return;
  }
  write(a / 10);
  putchar((char)('0' + (a % 10)));
}
void enter() {
  int n;
  read(n);
  int ok = 0;
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= n / 4; ++j) {
      char c = getchar();
      while (!isalnum(c)) c = getchar();
      if (c == '0') {
        if (ok == 1) {
          cout << 1;
          return;
        }
        ok = 2;
      } else if (c == 'F') {
        if (ok == 2) {
          cout << 1;
          return;
        }
        ok = 1;
      } else {
        cout << 1;
        return;
      }
    }
  cout << n;
}
void solve() {}
void print_result() {}
int main() {
  docfile();
  for (tt = 1; tt <= ntest; ++tt) {
    enter();
    solve();
    print_result();
  }
}
