#include<stdio.h>
int main(){
    int units;
    float bill=0.0;
    scanf("%d",&units);
    if(units<0){
        printf("Invalid input");
        return 0;
    }
    if(units<=100){
        bill=units*0.100;
    }
    else if(units<=200){
        bill=(100*0.10)+((units-100)*0.15);
    }
    else{
        bill=(100*0.10)+(100*0.15)+((units 200)*0.20);
    }
    prinf("%.2f",bill);
    return 0;
}