#include<stdio.h>
#include<math.h>
int minturns(float score){
    int turns=0;
    turns+=(int)score;
    score-=(int)score;
    if(score>=0.5-1e-6){
        turns++;
        score-=0.5;
    }
    int()
}

int main(){
    float score;
    scanf("%f",&score);
    int result=minturns(score);
    printf("%d\n",result);
    return 0;
}