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, core.stdc.string; void main() { auto N = readln.chomp.to!int; auto A = N.iota.map!(_ => readln.split.map!(to!long).array).array; long[long] comp; auto B = A.map!(a => a[1]).array.sort().uniq().array; auto M = B.length.to!int; foreach (i; 0..M) comp[B[i]] = i; foreach (i; 0..N) A[i][1] = comp[A[i][1]]; A.sort!"a[0] == b[0] ? a[1] < b[1] : a[0] > b[0]"(); auto st = new SegmentTree!(long, max, 0L)(M); foreach (i; 0..N) { auto b = A[i][1].to!int; auto v = st.query(b+1, M-1); auto x = st.query(b, b); st.assign(b, max(v + A[i][2], x)); } st.query(0, M-1).writeln; } class SegmentTree(T, alias op, T e) { T[] table; int size; int offset; this(int n) { size = 1; while (size <= n) size <<= 1; size <<= 1; table = new T[](size); fill(table, e); offset = size / 2; } void assign(int pos, T val) { pos += offset; table[pos] = val; while (pos > 1) { pos /= 2; table[pos] = op(table[pos*2], table[pos*2+1]); } } void add(int pos, T val) { pos += offset; table[pos] += val; while (pos > 1) { pos /= 2; table[pos] = op(table[pos*2], table[pos*2+1]); } } T query(int l, int r) { if (r < l) return e; return query(l, r, 1, 0, offset-1); } T query(int l, int r, int i, int a, int b) { if (b < l || r < a) { return e; } else if (l <= a && b <= r) { return table[i]; } else { return op(query(l, r, i*2, a, (a+b)/2), query(l, r, i*2+1, (a+b)/2+1, b)); } } }