#include <bits/stdc++.h>
using namespace std;
double f[2005][2005];
int n, t;
double p;
int main() {
  scanf("%d%lf%d", &n, &p, &t);
  f[0][0] = 1;
  for (int i = (0); i <= (int)t - 1; i++)
    for (int j = (0); j <= (int)n; j++) {
      if (j == n)
        f[i + 1][j] += f[i][j];
      else {
        f[i + 1][j] += f[i][j] * (1 - p);
        f[i + 1][j + 1] += f[i][j] * p;
      }
    }
  double ans = 0;
  for (int i = (0); i <= (int)n; i++) ans += f[t][i] * i;
  printf("%.10lf", ans);
  return 0;
}
