#include <bits/stdc++.h>
using namespace std;
template <class T>
T GCD(T x, T y) {
  return x ? GCD(y % x, x) : y;
}
int main() {
  int n, w, m;
  cin >> n >> w >> m;
  if (GCD(n, m) + n < m) {
    cout << "NO" << endl;
    return 0;
  } else {
    cout << "YES" << endl;
  }
  double d = w;
  int b = 1, r = 0;
  for (int i = 0; i < m; i++) {
    if (r >= n) {
      printf("%d %.6f\n", b, d * n / m);
      if (r == n) b++;
      r -= n;
      continue;
    }
    int rr = n;
    if (r) {
      printf("%d %.6f ", b, d * r / m);
      b++;
      rr -= r;
      r = m;
    }
    while (rr > 0) {
      if (rr <= m) {
        printf("%d %.6f ", b, d * rr / m);
        if (rr == m) b++;
        rr -= m;
        break;
      }
      printf("%d %.6f ", b, d);
      b++;
      rr -= m;
    }
    r = -rr;
    cout << endl;
  }
  return 0;
}
