local n, m = io.read("*n", "*n")
local c = {}
for i = 1, n do c[i] = i end
for i = 1, m do
  local idx = io.read("*n")
  local val = c[idx]
  for j = idx, 2, -1 do
    c[j] = c[j - 1]
  end
  c[1] = val
end
print(c[1])