#include <bits/stdc++.h>
using namespace std;
const int N = 2010;
int n, a[N], m;
double f[N][N], p, ans;
inline int read() {
  int x = 0;
  char ch = getchar();
  while (!isdigit(ch)) ch = getchar();
  while (isdigit(ch)) x = (x << 3) + (x << 1) + ch - 48, ch = getchar();
  return x;
}
int main() {
  scanf("%d%lf%d", &n, &p, &m);
  f[0][0] = 1;
  for (int i = 1; i <= m; i++) {
    f[i][0] = (1 - p) * f[i - 1][0];
    for (int j = 1; j <= n - 1; j++)
      f[i][j] = f[i - 1][j] * (1 - p) + f[i - 1][j - 1] * p;
    f[i][n] = f[i - 1][n] + f[i - 1][n - 1] * p;
  }
  for (int i = 1; i <= n; i++) ans += f[m][i] * i;
  printf("%lf", ans);
  return 0;
}
