local ffi = require 'ffi'
local C, ct = ffi.C, ffi.typeof 'int8_t[1]'
ffi.cdef 'int scanf(const char *, ...);'

print((function (p, n, m)
	local a={}
	for i=1,n do a[i]=(n+1)-i end
	for _=1,m do
		C.scanf("%d",p) local t=a[n+1-p[0]] for i=n+1-p[0],n-1 do a[i]=a[i+1] end a[n]=t
	end
	return a[n]
end)(ct(), io.stdin:read("*n"), io.stdin:read("*n")))