import sys
from collections import deque
import copy

from math import *

def get_read_func(fileobject):
    if fileobject == None :
        return raw_input
    else:
        return fileobject.readline


def main():
    if len(sys.argv) > 1:
        f = open(sys.argv[1])
    else:
        f = None
    read_func = get_read_func(f);
    input_raw = read_func().strip().split()
    [N] = [int(input_raw[0])]
    input_raw = read_func().strip().split()
    A = []
    for i in range(N):
        A.append(int(input_raw[i]))
    s = 0
    for i in range(N):
        s += A[i] - 1
    print s


if __name__ == '__main__':
    main()