89pts求调

#include <bits/stdc++.h>
#include <cctype>
#include <cstdio>
#include <cstdint>
uint8_t buf[1<<20], *p1, *p2;
using namespace std;
#define gc() (p1==p2 && (p2=(p1=buf)+fread(buf,1,1<<20,stdin)),*p1++)
int a[1010][1010],n;
int readint() {
	int k = 0, f = 1, c = gc();
	for (; !isdigit(c); c = gc()) if (c == '-') f = -1;
	for (; isdigit(c); c = gc()) k = k * 10 + (c ^ 48);
	return k * f;
}
int main() {
	n=readint();
	for (int i=1;i<=n;i++)
	    for (int j=1;j<=i;j++)
	        a[i][j]=readint();
	for (int i=n;i>1;i--)
	    for (int j=1;j<=i-1;j++)
	        a[i-j][j]+=max (a[i][j],a[i][j+1]);
    printf("%d",a[1][1]);
    return 0;
}