#include <bits/stdc++.h>
using namespace std;
const int MAXN = 50;
const int MAXM = 50;
int ans[MAXM][MAXN];
inline void inc(int &x, const int &n) {
  if (++x == n) {
    x = 0;
  }
}
void solve(void) {
  int n, m, w;
  cin >> n >> w >> m;
  w *= m;
  int v = n * w / m;
  int j = 0, left = v;
  for (int i = 0; i < n; i++) {
    if (left >= w) {
      ans[j][i] = w;
      if (left > w) {
        left -= w;
      } else {
        inc(j, m);
        left = v;
      }
      continue;
    }
    ans[j][i] = left;
    inc(j, m);
    int t = w - left;
    if (t > v) {
      cout << "NO\n";
      return;
    } else if (t == v) {
      ans[j][i] = v;
      inc(j, m);
      left = v;
    } else {
      ans[j][i] = t;
      left = v - t;
    }
  }
  cout << "YES\n";
  cout << fixed;
  cout.precision(6);
  for (int j = 0; j < m; j++) {
    bool flag = true;
    for (int i = 0; i < n; i++) {
      if (ans[j][i] > 0) {
        if (flag) {
          flag = false;
        } else {
          cout << ' ';
        }
        cout << i + 1 << ' ' << (double)ans[j][i] / m;
      }
    }
    cout << endl;
  }
}
int main(void) {
  solve();
  return 0;
}
