#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:256000000")
using namespace std;
int main() {
  int n, w, m;
  cin >> n >> w >> m;
  vector<vector<int> > a(n, vector<int>(m));
  for (int i = 0; i < m; ++i) {
    for (int j = i * n; j < (i + 1) * n; ++j) {
      a[j / m][j % m] = i + 1;
    }
  }
  for (int i = 0; i < n; ++i) {
    set<int> S;
    for (int j = 0; j < m; ++j) {
      S.insert(a[i][j]);
    }
    if (S.size() >= 3) {
      printf("NO\n");
      return 0;
    }
  }
  printf("YES\n");
  for (int i = 1; i <= m; ++i) {
    for (int j = 0; j < n; ++j) {
      int cnt = count(a[j].begin(), a[j].end(), i);
      if (cnt > 0) {
        printf("%d %.10lf ", j + 1, (double)(cnt) / (double)(m) * (double)(w));
      }
    }
    printf("\n");
  }
  return 0;
}
