#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define tup tuple<int, int, int>
const int nx = 2e5+5;
const int INF = 1e9;
int n, m, a[nx], vs[nx];
vector<int> dist(nx, INF);
vector<pii> adj[nx];
priority_queue<pii, vector<pii>, greater<pii>> pq;
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin >> n >> m;
for(int i=1;i<=n;i++) cin >> a[i];
for(int i=1;i<=m;i++)
{
int u, v;
cin >> u >> v;
int w = abs(a[u] - a[v]);
if(!w) w = 1;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
dist[1] = 0;
int cnt = 0;
pq.push({0, 1});
while(!pq.empty())
{
auto [w, u] = pq.top();
pq.pop();
if(w > dist[u]) continue;
//if(vs[u]) continue;
//vs[u] = 1;
// if(cnt++ > 50) return 0;
// cout << u << ' ' << w << '\n';
for(auto [v, nw] : adj[u])
{
if(dist[v] > dist[u] + nw)
{
dist[v] = dist[u] + nw;
pq.push({dist[v], v});
}
}
}
cout << dist[n] ;
return 0;
}
