import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


struct ModInt(int M_) {
  import std.conv : to;
  alias M = M_;
  int x;
  this(ModInt a) { x = a.x; }
  this(long a) { x = cast(int)(a % M); if (x < 0) x += M; }
  ref ModInt opAssign(long a) { return (this = ModInt(a)); }
  ref ModInt opOpAssign(string op)(ModInt a) {
    static if (op == "+") { x += a.x; if (x >= M) x -= M; }
    else static if (op == "-") { x -= a.x; if (x < 0) x += M; }
    else static if (op == "*") { x = cast(int)((cast(long)(x) * a.x) % M); }
    else static if (op == "/") { this *= a.inv(); }
    else static assert(false);
    return this;
  }
  ref ModInt opOpAssign(string op)(long a) {
    static if (op == "^^") {
      if (a < 0) return (this = inv()^^(-a));
      ModInt t2 = this, te = ModInt(1);
      for (long e = a; e > 0; e >>= 1) {
        if (e & 1) te *= t2;
        t2 *= t2;
      }
      x = cast(int)(te.x);
      return this;
    } else return mixin("this " ~ op ~ "= ModInt(a)");
  }
  ModInt inv() const {
    int a = x, b = M, y = 1, z = 0, t;
    for (; ; ) {
      t = a / b; a -= t * b;
      if (a == 0) {
        assert(b == 1 || b == -1);
        return ModInt(b * z);
      }
      y -= t * z;
      t = b / a; b -= t * a;
      if (b == 0) {
        assert(a == 1 || a == -1);
        return ModInt(a * y);
      }
      z -= t * y;
    }
  }
  ModInt opUnary(string op: "-")() const { return ModInt(-x); }
  ModInt opBinary(string op, T)(T a) const {
    return mixin("ModInt(this) " ~ op ~ "= a");
  }
  ModInt opBinaryRight(string op)(long a) const {
    return mixin("ModInt(a) " ~ op ~ "= this");
  }
  bool opCast(T: bool)() const { return (x != 0); }
  string toString() const { return x.to!string; }
}

enum MO = 1000000007;
alias Mint = ModInt!MO;


// a^-1 (mod m)
long modInv(long a, long m)
in {
  assert(m > 0, "modInv: m > 0 must hold");
}
do {
  long b = m, x = 1, y = 0, t;
  for (; ; ) {
    t = a / b; a -= t * b;
    if (a == 0) {
      assert(b == 1 || b == -1, "modInv: gcd(a, m) != 1");
      if (b == -1) y = -y;
      return (y < 0) ? (y + m) : y;
    }
    x -= t * y;
    t = b / a; b -= t * a;
    if (b == 0) {
      assert(a == 1 || a == -1, "modInv: gcd(a, m) != 1");
      if (a == -1) x = -x;
      return (x < 0) ? (x + m) : x;
    }
    y -= t * x;
  }
}


// M: prime, G: primitive root
class Fft(int M_, int G, int K) {
  import std.algorithm : reverse;
  import std.traits : isIntegral;
  alias M = M_;
  // 1, 1/4, 1/8, 3/8, 1/16, 5/16, 3/16, 7/16, ...
  int[] gs;
  this() {
    static assert(2 <= K && K <= 30, "Fft: 2 <= K <= 30 must hold");
    static assert(!((M - 1) & ((1 << K) - 1)), "Fft: 2^K | M - 1 must hold");
    gs = new int[1 << (K - 1)];
    gs[0] = 1;
    long g2 = G, gg = 1;
    for (int e = (M - 1) >> K; e; e >>= 1) {
      if (e & 1) gg = (gg * g2) % M;
      g2 = (g2 * g2) % M;
    }
    gs[1 << (K - 2)] = cast(int)(gg);
    for (int l = 1 << (K - 2); l >= 2; l >>= 1) {
      gs[l >> 1] = cast(int)((cast(long)(gs[l]) * gs[l]) % M);
    }
    assert((cast(long)(gs[1]) * gs[1]) % M == M - 1,
           "Fft: g^(2^(K-1)) == -1 (mod M) must hold");
    for (int l = 2; l <= 1 << (K - 2); l <<= 1) {
      foreach (i; 1 .. l) {
        gs[l + i] = cast(int)((cast(long)(gs[l]) * gs[i]) % M);
      }
    }
  }
  void fft(int[] xs) const {
    const n = cast(int)(xs.length);
    assert(!(n & (n - 1)), "Fft.fft: |xs| must be a power of two");
    assert(n <= 1 << K, "Fft.fft: |xs| <= 2^K must hold");
    for (int l = n; l >>= 1; ) {
      foreach (i; 0 .. (n >> 1) / l) {
        const(long) g = gs[i];
        foreach (j; (i << 1) * l .. (i << 1 | 1) * l) {
          const t = cast(int)((g * xs[j + l]) % M);
          if ((xs[j + l] = xs[j] - t) < 0) xs[j + l] += M;
          if ((xs[j] += t) >= M) xs[j] -= M;
        }
      }
    }
  }
  void invFft(int[] xs) const {
    const n = cast(int)(xs.length);
    assert(!(n & (n - 1)), "Fft.invFft: |xs| must be a power of two");
    assert(n <= 1 << K, "Fft.invFft: |xs| <= 2^K must hold");
    for (int l = 1; l < n; l <<= 1) reverse(xs[l .. l << 1]);
    for (int l = 1; l < n; l <<= 1) {
      foreach (i; 0 .. (n >> 1) / l) {
        const(long) g = gs[i];
        foreach (j; (i << 1) * l .. (i << 1 | 1) * l) {
          int t = cast(int)((g * (xs[j] - xs[j + l])) % M);
          if (t < 0) t += M;
          if ((xs[j] += xs[j + l]) >= M) xs[j] -= M;
          xs[j + l] = t;
        }
      }
    }
  }
  T[] convolute(T)(inout(T)[] as, inout(T)[] bs) const if (isIntegral!T) {
    const na = cast(int)(as.length), nb = cast(int)(bs.length);
    int n, invN = 1;
    for (n = 1; n < na + nb - 1; n <<= 1) {
      invN = ((invN & 1) ? (invN + M) : invN) >> 1;
    }
    auto xs = new int[n], ys = new int[n];
    foreach (i; 0 .. na) if ((xs[i] = cast(int)(as[i] % M)) < 0) xs[i] += M;
    foreach (i; 0 .. nb) if ((ys[i] = cast(int)(bs[i] % M)) < 0) ys[i] += M;
    fft(xs);
    fft(ys);
    foreach (i; 0 .. n) {
      xs[i] = cast(int)((((cast(long)(xs[i]) * ys[i]) % M) * invN) % M);
    }
    invFft(xs);
    auto cs = new T[na + nb - 1];
    foreach (i; 0 .. na + nb - 1) cs[i] = cast(T)(xs[i]);
    return cs;
  }
  ModInt!M[] convolute(inout(ModInt!M)[] as, inout(ModInt!M)[] bs) const {
    const na = cast(int)(as.length), nb = cast(int)(bs.length);
    int n, invN = 1;
    for (n = 1; n < na + nb - 1; n <<= 1) {
      invN = ((invN & 1) ? (invN + M) : invN) >> 1;
    }
    auto xs = new int[n], ys = new int[n];
    foreach (i; 0 .. na) xs[i] = as[i].x;
    foreach (i; 0 .. nb) ys[i] = bs[i].x;
    fft(xs);
    fft(ys);
    foreach (i; 0 .. n) {
      xs[i] = cast(int)((((cast(long)(xs[i]) * ys[i]) % M) * invN) % M);
    }
    invFft(xs);
    auto cs = new ModInt!M[na + nb - 1];
    foreach (i; 0 .. na + nb - 1) cs[i].x = xs[i];
    return cs;
  }
  int[] convolute(int M1)(inout(ModInt!M1)[] as, inout(ModInt!M1)[] bs) const
      if (M != M1) {
    const na = cast(int)(as.length), nb = cast(int)(bs.length);
    int n, invN = 1;
    for (n = 1; n < na + nb - 1; n <<= 1) {
      invN = ((invN & 1) ? (invN + M) : invN) >> 1;
    }
    auto xs = new int[n], ys = new int[n];
    foreach (i; 0 .. na) xs[i] = as[i].x;
    foreach (i; 0 .. nb) ys[i] = bs[i].x;
    fft(xs);
    fft(ys);
    foreach (i; 0 .. n) {
      xs[i] = cast(int)((((cast(long)(xs[i]) * ys[i]) % M) * invN) % M);
    }
    invFft(xs);
    return xs[0 .. na + nb - 1];
  }
}

alias Fft0 = Fft!(998244353, 3, 20);


// Fft3_0.M Fft3_1.M Fft3_2.M > 1.15 * 10^27, > 2^89.9
//*
enum FFT_K = 20;
alias Fft3_0 = Fft!(1045430273, 3, FFT_K);  // 2^20 997 + 1
alias Fft3_1 = Fft!(1051721729, 6, FFT_K);  // 2^20 1003 + 1
alias Fft3_2 = Fft!(1053818881, 7, FFT_K);  // 2^20 1005 + 1
//*/
// Fft3_0.M Fft3_1.M Fft3_2.M > 5.95 * 10^25, > 2^85.6
/*
enum FFT_K = 24;
alias Fft3_0 = Fft!(167772161, 3, FFT_K);  // 2^25 5 + 1
alias Fft3_1 = Fft!(469762049, 3, FFT_K);  // 2^26 7 + 1
alias Fft3_2 = Fft!(754974721, 11, FFT_K);  // 2^24 45 + 1
//*/
enum long FFT_INV01 = modInv(Fft3_0.M, Fft3_1.M);
enum long FFT_INV012 = modInv(cast(long)(Fft3_0.M) * Fft3_1.M, Fft3_2.M);
Fft3_0 FFT3_0;
Fft3_1 FFT3_1;
Fft3_2 FFT3_2;
void initFft3() {
  FFT3_0 = new Fft3_0;
  FFT3_1 = new Fft3_1;
  FFT3_2 = new Fft3_2;
}
// for negative result, if (!(0 <= c && c < <bound>)) add MMM:
//   enum MMM = 1L * Fft3_0.M * Fft3_1.M * Fft3_2.M;
long[] convolute(inout(long)[] as, inout(long)[] bs) {
  const cs0 = FFT3_0.convolute(as, bs);
  const cs1 = FFT3_1.convolute(as, bs);
  const cs2 = FFT3_2.convolute(as, bs);
  auto cs = new long[cs0.length];
  foreach (i; 0 .. cs0.length) {
    long d0 = cs0[i] % Fft3_0.M;
    long d1 = (FFT_INV01 * (cs1[i] - d0)) % Fft3_1.M;
    if (d1 < 0) d1 += Fft3_1.M;
    long d2 =
        (FFT_INV012 * ((cs2[i] - d0 - Fft3_0.M * d1) % Fft3_2.M)) % Fft3_2.M;
    if (d2 < 0) d2 += Fft3_2.M;
    cs[i] = d0 + Fft3_0.M * d1 + (cast(long)(Fft3_0.M) * Fft3_1.M) * d2;
  }
  return cs;
}
long[] convolute(inout(long)[] as, inout(long)[] bs, long m) {
  const cs0 = FFT3_0.convolute(as, bs);
  const cs1 = FFT3_1.convolute(as, bs);
  const cs2 = FFT3_2.convolute(as, bs);
  auto cs = new long[cs0.length];
  foreach (i; 0 .. cs0.length) {
    long d0 = cs0[i] % Fft3_0.M;
    long d1 = (FFT_INV01 * (cs1[i] - d0)) % Fft3_1.M;
    if (d1 < 0) d1 += Fft3_1.M;
    long d2 =
        (FFT_INV012 * ((cs2[i] - d0 - Fft3_0.M * d1) % Fft3_2.M)) % Fft3_2.M;
    if (d2 < 0) d2 += Fft3_2.M;
    cs[i] =
        (d0 + Fft3_0.M * d1 + ((cast(long)(Fft3_0.M) * Fft3_1.M) % m) * d2) % m;
  }
  return cs;
}
ModInt!M[] convolute(int M)(inout(ModInt!M)[] as, inout(ModInt!M)[] bs) {
  const cs0 = FFT3_0.convolute(as, bs);
  const cs1 = FFT3_1.convolute(as, bs);
  const cs2 = FFT3_2.convolute(as, bs);
  auto cs = new ModInt!M[cs0.length];
  foreach (i; 0 .. cs0.length) {
    long d0 = cs0[i] % Fft3_0.M;
    long d1 = (FFT_INV01 * (cs1[i] - d0)) % Fft3_1.M;
    if (d1 < 0) d1 += Fft3_1.M;
    long d2 =
        (FFT_INV012 * ((cs2[i] - d0 - Fft3_0.M * d1) % Fft3_2.M)) % Fft3_2.M;
    if (d2 < 0) d2 += Fft3_2.M;
    cs[i] =
        (d0 + Fft3_0.M * d1 + ((cast(long)(Fft3_0.M) * Fft3_1.M) % M) * d2) % M;
  }
  return cs;
}


enum LIM = 2 * 10^^5 + 10;
Mint[] inv, fac, invFac;
void prepare() {
  inv = new Mint[LIM];
  fac = new Mint[LIM];
  invFac = new Mint[LIM];
  inv[1] = 1;
  foreach (i; 2 .. LIM) {
    inv[i] = -(Mint.M / i) * inv[cast(size_t)(Mint.M % i)];
  }
  fac[0] = invFac[0] = 1;
  foreach (i; 1 .. LIM) {
    fac[i] = fac[i - 1] * i;
    invFac[i] = invFac[i - 1] * inv[i];
  }
}
Mint binom(long n, long k) {
  if (0 <= k && k <= n) {
    assert(n < LIM);
    return fac[cast(size_t)(n)] * invFac[cast(size_t)(k)] * invFac[cast(size_t)(n - k)];
  } else {
    return Mint(0);
  }
}


Mint calc(int n, int k) {
  return Mint(n - k + 1) * Mint(n + 1)^^(k - 1);
}

void main() {
  initFft3;
  prepare;
  
  /*
  debug {
    foreach (n; 1 .. 7 + 1) foreach (k; 1 .. n + 1) {
      int cnt;
      foreach (p; 0 .. n^^k) {
        auto freq = new int[n];
        foreach (i; 0 .. k) {
          ++freq[p / n^^i % n];
        }
        foreach_reverse (j; 0 .. n - 1) {
          freq[j] += freq[j + 1];
        }
        bool ok = true;
        foreach (j; 0 .. n) {
          ok = ok && (freq[j] <= n - j);
        }
        if (ok) {
          ++cnt;
          if (n <= 4) {
            writeln(iota(n).map!(i => (p / n^^i % n)));
          }
        }
      }
      writeln(n, " ", k, ": ", cnt);
      assert(cnt == (n - k + 1) * (n + 1)^^(k - 1));
    }
  }
  //*/
  
  try {
    for (; ; ) {
      const N = readInt();
      const M = readInt();
      auto S = readToken();
      if (S[0] == '-' && S[M - 1] == 'o') {
        S = S.dup.reverse;
      }
      
      alias Interval = Tuple!(int, "l", int, "r");
      Interval[] ps;
      for (int i = 0, j; i < M; i = j) {
        for (j = i; j < M && S[i] == S[j]; ++j) {}
        if (S[i] == '-') {
          ps ~= Interval(i, j);
        }
      }
      const psLen = cast(int)(ps.length);
      debug {
        writeln("ps = ", ps);
      }
      
      Mint ans;
      if (psLen == 0) {
        foreach (k; 0 .. N - M + 1) {
          ans += calc(N - M, k) * Mint(N)^^(N - k);
        }
      } else if (psLen == 1 && ps[0] == Interval(0, M)) {
        // for each length
        
      } else if (ps[0].l == 0 && ps[psLen - 1].r == M) {
        // EGF convolution
        
      } else if (ps[0].l == 0) {
        assert(false);
      } else if (ps[psLen - 1].r == N) {
        // mendou
        
      } else {
        // futsuu
        
      }
      ans *= (N - M);
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}