[백준] 1932번 정수 삼각형

n=int(input())
triangle=[]
dp=[[0]*n for _ in range(n)]
for i in range(n):
    triangle.append(list(map(int,input().split())))


dp[0][0]=triangle[0][0]
for i in range(1,n):
    for j in range(i+1):
        if j==0:
            dp[i][j]=dp[i-1][j]+triangle[i][j]
        elif j==i:
            dp[i][j]=dp[i-1][j-1]+triangle[i][j]
        else:
            dp[i][j]=max(dp[i-1][j-1],dp[i-1][j])+triangle[i][j]

print(max(dp[n-1]))