#include<stdio.h>

int main(){
    int units;
    scanf("%d",&units);
    
    if(units<0){
        printf("Invalid input");
        return 0;
    }
    float bill=0.0;

    if(units <= 100){
        bill = units*0.10;
    }
    else if(units <= 200){
        bill = 100*0.10+(units-100)*0.15;
    }
    else{
        bill = 100*0+10*0.15+(units-200)*0.20
    }
    }
}