#include <stdio.h>

int main(){
    long long holiday1, holiday2, all;
    scanf("%lld%lld%lld",&holiday1,&holiday2,&all);

    int i = 1;
    int count = 0;
    while(i <= all){
       if(holiday1 != i && holiday2 != i){
            count++;
       } 
       i++;
    }
    printf("%lld",count);
}