#include <bits/stdc++.h>   using namespace std;   inline long long read() {     long long x = 0;     char ch = getchar();     bool f = 0;     for (; !isdigit(ch); ch = getchar())       if (ch ==  - ) f = 1;     for (; isdigit(ch); ch = getchar()) x = x * 10 + ch -  0 ;     return f ? -x : x;   }   void write(long long x) {     if (x < 0) putchar( - ), x = -x;     if (x >= 10) write(x / 10);     putchar(x % 10 +  0 );   }   void writeln(long long x) {     write(x);     putchar(  n );   }   void writep(long long x) {     write(x);     putchar(   );   }   long long const N = 1e6 + 3;   long long n, a[N];   signed main() {     n = read();     long long ans = 0;     for (long long i = 1; i <= n; i++) a[i] = read(), ans += a[i];     if (n == 1) {       writeln(a[1]);       return 0;     }     sort(a + 1, a + n + 1);     if (a[1] <= 0) {       for (long long i = 1; i < n && a[i] <= 0; i++) ans -= 2 * a[i];     } else {       ans -= 2 * a[1];     }     writeln(ans);   }   