#include <stdio.h>

int main() {
    int N, K, W;
    scanf("%d %d %d", &N, &K, &W);

    int total = N;
    int used = N;
    
    while (used >= K) {
        int exchange = used / K * W;
        total += exchange;
        used = exchange + used % K;
    }

    printf("%d\n", total);

    return 0;
}