function foo() {
var a = [];
var b = [];
for (var i = 0; i < 1000; ++i) {
a.push(i + 1);
b.push(i - 1);
}
for (var i = 0; i < 1000; ++i) {
for (var j = 0; j < a.length; ++j)
a[j] += b[j];
for (var j = 0; j < a.length; ++j)
a[j] -= b[j];
}
var result = 0;
for (var i = 0; i < a.length; ++i)
result += a[i];
return result;
}
if (foo() != 500500)
throw "ERROR";