lst=[["x^3*asech(b*x+a)","x",1],
["x^2*asech(b*x+a)","x",1],
["x*asech(b*x+a)","x",1],
["asech(b*x+a)","x",1],
["asech(b*x+a)/x","x",1],
["asech(b*x+a)/x^2","x",1],
["asech(b*x+a)/x^3","x",1],
["asech(b*x+a)/x^4","x",1],
["x^2*asech(b*x+a)^2","x",1],
["x*asech(b*x+a)^2","x",1],
["asech(b*x+a)^2","x",1],
["asech(b*x+a)^2/x","x",1],
["asech(b*x+a)^2/x^2","x",1],
["asech(b*x+a)^2/x^3","x",1],
["x*asech(b*x+a)^3","x",1],
["asech(b*x+a)^3","x",1],
["asech(b*x+a)^3/x","x",1],
["asech(b*x+a)^3/x^2","x",1],
["asech(b*x+a)^3/x^3","x",1],
["x^3*asech(x^(1/2))","x",1],
["x^2*asech(x^(1/2))","x",1],
["x*asech(x^(1/2))","x",1],
["asech(x^(1/2))","x",1],
["asech(x^(1/2))/x","x",1],
["asech(x^(1/2))/x^2","x",1],
["asech(x^(1/2))/x^3","x",1],
["asech(x^(1/2))/x^4","x",1],
["asech(1/x)","x",1],
["asech(a*x^n)/x","x",1],
["asech(a*x^5)/x","x",1],
["asech(c*exp(b*x+a))","x",1],
["asech(b*x+a)/(a*d/b+d*x)","x",1],
["x^3*asech(b*x^4+a)","x",1],
["x^(-1+n)*asech(a+b*x^n)","x",1]]