import os, sys
import math, decimal, queue, heapq, bisect, itertools, functools, collections, string
from bisect import bisect, bisect_left
from collections import defaultdict, OrderedDict, deque, Counter
from functools import cmp_to_key, lru_cache, reduce
from heapq import heapify, heappush, heappushpop, heappop, heapreplace, nlargest, nsmallest
from itertools import accumulate, chain, combinations, combinations_with_replacement, compress, count, cycle, dropwhile, filterfalse, groupby, islice, permutations, product, repeat, starmap, takewhile, tee, zip_longest
from math import gcd, factorial, isqrt, comb, perm, prod, inf
from queue import Queue, PriorityQueue, LifoQueue
from string import ascii_letters, ascii_lowercase, ascii_uppercase, digits, hexdigits, octdigits

LOCAL = sys.argv[0] if '4a' in sys.argv[0] else None

P = lambda *p: [print(i, end='	') for i in p] if LOCAL else None
PI = lambda *p: print(' '.join(map(str, p))) or None
PII = lambda X: [PI(*row) for row in X]

sys.stdin = open(os.path.join(os.getcwd(), 'a1.txt'), 'r') if LOCAL else sys.stdin
I = lambda: [int(a) for l in sys.stdin for a in l.strip().split()]
S = lambda: [a for l in sys.stdin for a in l.strip().split()]
IM = lambda: [[int(a) for a in l.split()] for l in sys.stdin]
SM = lambda: [[a for a in l.split()] for l in sys.stdin]

az, AZ, mod = ascii_lowercase, ascii_uppercase, 1_000_000_007

X = I()
# P(A)


def solution(X):
    def find_remainder(A, B):
        r = A % B
        if r < 0:
            r += abs(B)
        return r
    A, B = X
    print(find_remainder(A, B))


solution(X)