#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
// if you end up using long double, you need to set the floating point notation to fixed, and set the percision to be very high
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

const ll INF = 2001001001;
const ll INF2 = 2e18;
const ll MOD = 1000000007;

#define max3(a, b, c) max(a, max(b, c))
#define min3(a, b, c) min(a, min(b, c))
#define pb push_back 
#define pf push_front
#define f first
#define s second
#define mp make_pair
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)

const bool testing = 0;
mt19937 rng(63);

// first four are north, west, east ,south
int dir1[] = {1, 0, -1, 0, 1, 1, -1, -1};
int dir2[] = {0, 1, 0, -1, 1, -1, 1, -1};

int main() {
	// apparently this does fast i/o
	cin.tie(0) , ios::sync_with_stdio(0);
	cin.exceptions(cin.failbit);
	
	stringstream ss;
	
    int n, m, k;
    cin >> n >> m >> k;
    vector<ll> petals(n+1, 0);
    for(int i = 1; i <= n; i++){
        int a;
        cin >> a;
        a--;
        petals[i] = a;
    }
    vector<vi> vec(n+1);
    vector<int> indegs(n+1, 0);
    for(int i = 0; i < m; i++){
        int a, b;
        cin >> a >> b;
        vec[a].pb(b);
        indegs[b]++;
    }
    ll sum = 0;
    queue<int> q;
    for(int i = 1; i <= n; i++){
        if(indegs[i] == 0) q.push(i);
    }
    vector<pii> ops; // for double checking
    vector<ll> petals_copy(petals);
    while(sz(q)){
        int curr = q.front();
        q.pop();
        ll diff = k-1 - petals[curr];
        petals[curr] = 0;
        for(auto a : vec[curr]){
            petals[a] = (petals[a] + diff) % k;
            indegs[a]--;
            if(indegs[a] == 0){
                q.push(a);
            }
        }
        sum += diff;
        ops.pb({curr, diff});
    }
    cout << sum << "\n";

    // double check
    for(auto p : ops){
        petals_copy[p.f] += p.s;
        for(auto a : vec[p.f]){
            petals_copy[a] += p.s;
        }
    }
    for(int i = 1; i <= n; i++){
        assert(petals_copy[i] % k == k-1);
    }
	cout << ss.str();
	return 0;
}