#include<bits/stdc++.h>
#define pb emplace_back
using namespace std;
using ll = long long;
#ifdef KEV
#define DE(args...) cerr << #args << " = ", kout(args)
void kout() {cerr << endl;}
template<class T1, class ...T2>
void kout (T1 v, T2 ...e) { cerr << v << ", ", kout(e...); }
void debug(auto L, auto R) { while (L != R) cerr << *L << " \n"[next(L)==R], ++L; }
#else
#define DE(...) 0
void debug(...) {}
#endif
const int maxn = 500010;
int n, m;
char a[maxn], b[maxn], c[maxn<<1];
int za[maxn], zb[maxn], zc[maxn<<1];
void build(char c[], char a[], int z[], int za[]) {
#define W(i) (i <= m ? c[i] : a[i - m - 1])

    for (int i = 1, l = 0, r = 0;i <= n+m;++i) {
        z[i] = max(0, min(z[ i - l ], r - i + 1));
        while (i + z[i] <= n+m && W(z[i]) == W(z[i]+i))
            l = i, r = i + z[i]++;
    }
    for (int i = 0;i < n;++i)
        za[i] = z[i + m + 1];
}
void init() {
    build(c, a, zc, za);
    reverse(c, c+m);
    reverse(b, b+n);
    build(c, b, zc, zb);
    reverse(c, c+m);
    reverse(b, b+n);
    reverse(zb, zb+n);

    for (int i = 0;i < n;++i) {
        if (za[i] == m) --za[i];
        if (zb[i] == m) --zb[i];
    }
    debug(za, za+n);
    debug(zb, zb+n);
}
int ca[maxn], cb[maxn];
ll sa[maxn], sb[maxn];
ll res;
struct bit {
    ll v[maxn];
    void add(int i, ll val) {
        for (;i <= n;i += i&-i)
            v[i] += val;
    }
    ll query(int i) {
        ll res = 0;
        for (;i;i ^= i&-i)
            res += v[i];
        return res;
    }
}t1, t2;
void minu() {
}

void solve() {
    init();
    for (int i = 0;i < n;++i)
        ++ca[ za[i] ], ++cb[ zb[i] ];
    for (int i = 1;i <= n;++i)
        sa[i] = sa[i-1] + ca[i] * (ll)i, ca[i] += ca[i-1];

    for (int i = 1;i <= n && i < m;++i) if (cb[i] && m - i <= n) {
        ll ad = (sa[n] - sa[ m - i - 1]) - (m-i-1) * (ca[n] - ca[ m - i - 1]);
        res += ad * cb[i];
    }
    DE(res);
    minu();
}
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    cin >> n >> m >> a >> b >> c;
    solve();
    cout << res << '\n';
}