#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <math.h>
int main(void)
{
    int suburicnt=0,yasumi1,yasumi2,day;
    scanf("%d %d %d",&yasumi1,&yasumi2,&day);
    for(int i=1;i<=day;i++)
    {
        if(i==yasumi1||i==yasumi2)
        {
            continue;
        }
        suburicnt++;
    }
    printf("%d",suburicnt);
}