# BOJ - 14588 - Line Friends (Small)

Updated:

```
import sys
_INF = 1e9
def check(x, y, vector):
if vector[x][1] < vector[y][0] or vector[y][1] < vector[x][0]: return 0
else: return 1
def solution():
N = int(sys.stdin.readline())
dist = [[_INF for _ in range(N)] for _ in range(N)]
vector = []
for i in range(N):
dist[i][i] = 0
for _ in range(N):
L, R = map(int, sys.stdin.readline().split())
vector.append((L, R))
for i in range(N):
for j in range(N):
if check(i, j, vector):
dist[i][j] = 1
dist[j][i] = 1
for k in range(N):
for i in range(N):
for j in range(N):
if dist[i][j] > dist[i][k] + dist[k][j]:
dist[i][j] = dist[i][k] + dist[k][j]
Q = int(sys.stdin.readline())
for _ in range(Q):
A, B = map(int, sys.stdin.readline().split())
print(-1 if dist[A-1][B-1] == _INF else dist[A-1][B-1])
solution()
```

https://www.acmicpc.net/problem/14588

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