#include <bits/stdc++.h>
using namespace std;
vector<int> a[55], b[55];
int f[55][55];
int main(void) {
  int n, w, m;
  scanf("%d %d %d", &n, &w, &m);
  double c = w / double(m);
  int p = 0, r = m;
  for (int i = 0; i < m; ++i) {
    int q = n;
    while (q > 0) {
      int z = min(r, q);
      a[i].push_back(p);
      b[i].push_back(z);
      f[p][i] = 1;
      q -= z, r -= z;
      if (r == 0) p++, r = m;
    }
  }
  for (int i = 0; i < n; ++i) {
    int c = 0;
    for (int j = 0; j < m; ++j) c += f[i][j];
    if (c > 2) {
      puts("NO");
      return 0;
    }
  }
  puts("YES");
  for (int i = 0; i < m; ++i) {
    for (int j = 0; j < a[i].size(); ++j)
      printf("%d %lf ", a[i][j] + 1, c * b[i][j]);
    putchar('\n');
  }
  return 0;
}
