$A=01,B=02,C=03,$dots,$Z=26.$

$233129242$

Since $d=307=256+32+16+2+1,$ find the first letter of the decrypted message by computing ${233}^d$ mod $713.$ Now

${233}^1-=a(mod713),{233}^2-=b(mod713),{233}^4-=c(mod713)$

${233}^8-=d(mod713),{233}^{16}-=e(mod713),{233}^{32}-=f(mod713)$

${233}^{64}-=g(mod713),{233}^{128}-=h(mod713),{233}^{256}-=i(mod713).$

Thus, ${233}^{307}$mod$713=(a*b*e*f*i)mod713=,,$ and so the first letter in the encrypted message is

Repeat these computations for each encrypted letter and find the completed decrypted message.