int f91(int N){
    if(N >= 101){
        return N-10;
    }
    if(N <= 100){
        return f91(f91(N+11));
    }
}
int main(int argc, char const* argv[])
{
    int n;
    while(scanf("%d",&n) && n != 0){
        printf("f91(%d) = %d\n",n,f91(n));
    }

    return 0;
}