#include <stdio.h>

main() {
    int X, Y, L;
    int count = 0;
    
    scanf("%d", &X);
    scanf("%d", &Y);
    scanf("%d", &L);
    
    if (Y < 0) {
        count = 1;
        Y = -Y;
    }
    
    count += Y/L;
    if (Y%L > 0)
        count++;
    
    if (X < 0) {
        X = -X;
        count++;
    } else if (X > 0) {
       count++;
    }
    
    count += X/L;
    if (X%L > 0)
        count++;
        
    printf("%d\n", count);
}