#include <stdio.h>
#include <stdlib.h>

int main(int argc, const char * argv[]) {
    
    int A,B,S;
    scanf("%d %d %d",&A,&B,&S);
    
    if(abs(S-A) <= abs(S-B)){
        printf("%d\n",S + abs(S -A));
    }
    else if(A!=0){
        printf("%d\n",abs(S-B) + abs(S-A) + A);
    }
    else{
        printf("%d\n",abs(S-B) + S +1);
    }
    
    return 0;
    
}