import sys
import numpy as np
from scipy.linalg import norm
from scipy.sparse.csgraph import dijkstra
from scipy.sparse import csr_matrix

input = sys.stdin.buffer.readline

int1 = lambda x: int(x) - 1


def main():
    N, M = map(int, input().split())
    X, Y = map(int1, input().split())
    pole = np.array([tuple(map(int, input().split())) for _ in range(N)])
    wire = np.array([tuple(map(int1, input().split())) for _ in range(M)]).T
    length = norm(pole[wire[0]] - pole[wire[1]], axis=1)
    matr = csr_matrix((length, wire), shape=(N, N))
    print(dijkstra(matr, indices=X, directed=False)[Y])


if __name__ == '__main__':
    main()