X=int(input())
Y=int(input())
K=int(input())

if X==Y==0:
    print(0)
elif X==0:
    if Y>0:
        print((Y+K-1)//K)
    else:
        Y=abs(Y)
        X=abs(X)
        print((Y+K-1)//K+2)
        
elif Y==0:
    Y=abs(Y)
    X=abs(X)
    print((X+K-1)//K+1)
else:
    if Y>0:
        Y=abs(Y)
        X=abs(X)
        print((Y+K-1)//K+(X+K-1)//K+1)
    else:
        Y=abs(Y)
        X=abs(X)
        print((Y+K-1)//K+(X+K-1)//K+2)