import std;

void main () {
    int N = readln.chomp.to!int;
    auto A = new int[](N);
    auto B = new int[](N);
    foreach (i; 0 .. N) {
        readln.read(A[i], B[i]);
    }

    auto dp = new long[][](N + 1, N + 1);
    foreach (i; 0 .. N + 1) {
        dp[i][] = -long.max;
    }

    foreach (i; 0 .. N + 1) {
        dp[0][] = 0;
    }

    foreach (i; 0 .. N) {
        foreach (j; 0 .. N + 1) {
            if (dp[i][j] == -long.max) {
                continue;
            }

            // 攻撃する
            if (0 <= j - 1) {
                dp[i + 1][j - 1] = max(dp[i + 1][j - 1], dp[i][j] + B[i]);
            }

            // 攻撃しない
            dp[i + 1][j] = max(dp[i + 1][j], dp[i][j] + 1L * A[i] * j);
        }
    }

    writeln(dp[N][0]);
}

void read (T...) (string S, ref T args) {
    import std.conv : to;
    import std.array : split;
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}