import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop;

immutable long MOD = 10^^9 + 7;

void main() {
    auto N = readln.chomp.to!int;
    auto A = readln.split.map!(to!long).array;

    long ans = 0;

    foreach (i; 0..N) if (A[i] != N) ans += i + 1; else ans -= i + 1;

    writeln(max(ans, 0));
}