#!/usr/bin/python
from collections import deque
def remove_nth(d, n):
    d.rotate(-n)
    res = d.popleft()
    d.rotate(n)
    return res

n, _ = map(int, raw_input().split())
stk = deque(xrange(1, n+1))
a = map(lambda x: int(x)-1, raw_input().split())
for i in a:
    stk.appendleft(remove_nth(stk, i))
print stk.popleft()