#include <iostream>
#include <iomanip>
#include <string>
#include <cassert>
#include <cstring>
#include <algorithm>

using namespace std;

typedef long long Int;
const Int B = 10000000000;      // base (power of 10)
const int BW = 10;         // log B
const int MAXDIGIT = 5000; // it can represent BW*MAXDIGIT digits (in base 10)
struct BigNum {
    Int digit[MAXDIGIT];
    int size;
    BigNum(int size = 1, Int a = 0) : size(size) {
        memset(digit, 0, sizeof(digit));
        digit[0] = a;
    }
};
const BigNum ZERO(1, 0), ONE(1, 1);

// Comparators
inline bool operator<(const BigNum & x, const BigNum & y) {
    if (x.size != y.size) return x.size < y.size;
    for (int i = x.size - 1; i >= 0; --i)
    if (x.digit[i] != y.digit[i]) return x.digit[i] < y.digit[i];
    return false;
}
inline bool operator >(const BigNum & x, const BigNum &  y) { return y < x; }
inline bool operator<=(const BigNum &  x, const BigNum &  y) { return !(y < x); }
inline bool operator>=(const BigNum &  x, const BigNum &  y) { return !(x < y); }
inline bool operator!=(const BigNum &  x, const BigNum &  y) { return x < y || y < x; }
inline bool operator==(const BigNum &  x, const BigNum &  y) { return !(x < y) && !(y < x); }

// Utilities
inline BigNum normal(BigNum x) {
    Int c = 0;
    for (int i = 0; i < x.size; ++i) {
        while (x.digit[i] < 0)
            x.digit[i + 1] -= 1, x.digit[i] += B;
        Int a = x.digit[i] + c;
        x.digit[i] = a % B;
        c = a / B;
    }
    for (; c > 0; c /= B) x.digit[x.size++] = c % B;
    while (x.size > 1 && x.digit[x.size - 1] == 0) --x.size;
    return x;
}
inline BigNum convert(Int a) {
    return normal(BigNum(1, a));
}
inline BigNum convert(const string &s) {
    BigNum x;
    int i = s.size() % BW;
    if (i > 0) i -= BW;
    for (; i < (int)s.size(); i += BW) {
        Int a = 0;
        for (int j = 0; j < BW; ++j)
            a = 10 * a + (i + j >= 0 ? s[i + j] - '0' : 0);
        x.digit[x.size++] = a;
    }
    reverse(x.digit, x.digit + x.size);
    return normal(x);
}
// Input/Output
ostream &operator<<(ostream &os, const BigNum & x) {
    os << x.digit[x.size - 1];
    for (int i = x.size - 2; i >= 0; --i)
        os << setw(BW) << setfill('0') << x.digit[i];
    return os;
}
istream &operator>>(istream &is, BigNum &x) {
    string s; is >> s;
    x = convert(s);
    return is;
}

// Basic Operations 
inline BigNum operator+(BigNum x, const BigNum & y) {
    if (x.size < y.size) x.size = y.size;
    for (int i = 0; i < y.size; ++i)
        x.digit[i] += y.digit[i];
    return normal(x);
}
inline BigNum operator-(BigNum x, const BigNum & y) {
    assert(x >= y);
    for (int i = 0; i < y.size; ++i)
        x.digit[i] -= y.digit[i];
    return normal(x);
}
inline BigNum operator*(BigNum x, const BigNum & y) {
    BigNum z(x.size + y.size);
    for (int i = 0; i < x.size; ++i)
    for (int j = 0; j < y.size; ++j)
        z.digit[i + j] += x.digit[i] * y.digit[j];
    return normal(z);
}
inline BigNum operator*(BigNum x, Int a) {
    for (int i = 0; i < x.size; ++i)
        x.digit[i] *= a;
    return normal(x);
}
inline pair<BigNum, Int> divmod(BigNum x, Int a) {
    Int c = 0, t;
    for (int i = x.size - 1; i >= 0; --i) {
        t = B * c + x.digit[i];
        x.digit[i] = t / a;
        c = t % a;
    }
    return pair<BigNum, Int>(normal(x), c);
}
inline BigNum operator/(BigNum x, Int a) {
    return divmod(x, a).first;
}
inline Int operator%(BigNum x, Int a) {
    return divmod(x, a).second;
}
inline pair<BigNum, BigNum> divmod(BigNum x, BigNum y) {
    if (x.size < y.size) return pair<BigNum, BigNum>(ZERO, x);
    int F = B / (y.digit[y.size - 1] + 1); // multiplying good-factor
    x = x * F; y = y * F;
    BigNum z(x.size - y.size + 1);
    for (int k = z.size - 1, i = x.size - 1; k >= 0; --k, --i) {
        z.digit[k] = (i + 1 < x.size ? x.digit[i + 1] : 0) * B + x.digit[i];
        z.digit[k] /= y.digit[y.size - 1];
        BigNum t(k + y.size);
        for (int m = 0; m < y.size; ++m)
            t.digit[k + m] = z.digit[k] * y.digit[m];
        t = normal(t);
        while (x < t) {
            z.digit[k] -= 1;
            for (int m = 0; m < y.size; ++m)
                t.digit[k + m] -= y.digit[m];
            t = normal(t);
        }
        x = x - t;
    }
    return pair<BigNum, BigNum>(normal(z), x / F);
}
inline BigNum operator/(BigNum x, BigNum y) {
    return divmod(x, y).first;
}
inline BigNum operator%(BigNum x, BigNum y) {
    return divmod(x, y).second;
}

// Advanced Operations
inline BigNum shift(BigNum x, int k) {
    if (x.size == 1 && x.digit[0] == 0) return x;
    x.size += k;
    for (int i = x.size - 1; i >= k; --i) x.digit[i] = x.digit[i - k];
    for (int i = k - 1; i >= 0; --i) x.digit[i] = 0;
    return x;
}
inline BigNum sqrt(const BigNum & x) { // verified UVA 10023
    const BigNum _20 = convert(2 * B);
    BigNum odd = ZERO;
    BigNum rem(2, 0);
    BigNum ans = ZERO;
    for (int i = 2 * ((x.size - 1) / 2); i >= 0; i -= 2) {
        int group = (i + 1 < x.size ? x.digit[i + 1] : 0) * B + x.digit[i];
        odd = _20 * ans + ONE;
        rem = shift(rem, 2) + convert(group);
        int count = 0;
        while (rem >= odd) {
            count = count + 1;
            rem = rem - odd;
            odd.digit[0] += 2;
            odd = normal(odd);
        }
        ans = shift(ans, 1) + convert(count);
    }
    return ans;
}


int main(){
    int n, m, r; cin >> n >> m >> r;
    int x = r - n*m + n - 1;
    int y = r - m * n;
    BigNum ans;
    if (y < 0 || x < 0) ans = ZERO;
    else
    {
        ans = convert(1);
        for (int i = 1; i <= y; i++){
            ans = ans * (x - i + 1);
            ans = ans / i;
        }
    }
    cout << ans << endl;
}

Measured memory_bytes: 1680