#include <bits/stdc++.h>
using namespace std;
double fabs(double a, double b) { return a - b > 0.0000001 ? a - b : b - a; }
int main() {
  double n, w, m;
  scanf("%lf %lf %lf", &n, &w, &m);
  double k = n * w / m, t = 0;
  int flag = 0;
  for (int i = 1; i < m; i++) {
    if (k - t < 0.0000001 && fabs(k, t) < 0.0000001) {
      t = 0;
    } else if (k - t - w < 0.0000001) {
      if (fabs(k - t, w) < 0.0000001) {
        t = 0;
      } else {
        t = w - k + t;
        if (k - t < 0.0000001 && fabs(k, t) > 0.0000001) {
          flag = 1;
          break;
        }
      }
    } else {
      int j = 1;
      while (k - t - j * w > 0.0000001) {
        j++;
      }
      if (fabs(k - t, j * w) < 0.0000001) {
        t = 0;
      } else {
        t = j * w - k + t;
        if (k - t < 0.0000001 && fabs(k, t) > 0.0000001) {
          flag = 1;
          break;
        }
      }
    }
  }
  if (flag) {
    printf("NO\n");
    return 0;
  }
  printf("YES\n");
  int ss = 1;
  t = 0;
  int ans = 0;
  for (int i = 1; i <= m; i++) {
    if (fabs(k, t) < 0.0000001) {
      printf("\n");
      t = 0;
      ans = 0;
      continue;
    }
    if (k - t - w < 0.0000001) {
      if (fabs(k - t, w) < 0.0000001) {
        t = 0;
        if (!ans) {
          printf("%d %.6lf\n", ss++, w);
        } else {
          printf(" %d %.6lf\n", ss++, w);
        }
        ans = 0;
      } else {
        if (ans) {
          printf(" %d %.6lf\n", ss, k - t);
        } else {
          printf("%d %.6lf\n", ss, k - t);
        }
        t = w - k + t;
        printf("%d %.6lf", ss++, t);
        ans = 1;
      }
    } else {
      int j = 1;
      while (k - t - j * w > 0.0000001) {
        j++;
      }
      if (fabs(k - t, j * w) < 0.0000001) {
        t = 0;
        for (int s = i; s < i + j; s++) {
          if (!ans) {
            printf("%d %.6lf", ss++, w);
            ans = 1;
          } else {
            printf(" %d %.6lf", ss++, w);
          }
        }
        printf("\n");
        ans = 0;
      } else {
        for (int s = 1; s < j; s++) {
          if (!ans) {
            printf("%d %.6lf", ss++, w);
            ans = 1;
          } else {
            printf(" %d %.6lf", ss++, w);
          }
        }
        t = j * w - k + t;
        printf(" %d %.6lf\n", ss, w - t);
        printf("%d %.6lf", ss++, t);
        ans = 1;
      }
    }
  }
  return 0;
}
